Later Platonism
The Theaetetus was a popular dialogue in classical antiquity. Writing in the 1st century BCE, the Middle Platonist Eudorus of Alexandria references the definition of a philosopher as a "likeness to a god"[ao] and uses it to justify his synthesis of Platonism with Pythagorean teachings on virtue.[7] One of Eudorus's contemporaries, Philo of Alexandria also quoted from it frequently, implying that he considered it an important work.[7] The Theaetetus was also the subject of many philosophical commentaries. The earliest surviving Platonic commentary, dating from between the 1st century BCE and the 2nd century CE, is a commentary on the Theaetetus, which goes into detail on the nature of knowledge outlined in the work and compares it to the definitions of knowledge outlined in the Meno and the Sophist.[8] The Theaetetus is also referenced frequently by Alcinous in his Handbook of Platonism.[9]
In Late antiquity, the work was included in the Neoplatonic curriculum of twelve dialogues developed by Iamblichus, where it was preceded by the Cratylus, and considered a theoretical work on logic.[10]
Gettier problems
In the 20th century, the dialogue and its definition of knowledge as a "Justified True Belief" were investigated by Edmund Gettier, who investigated Platonic epistemology as related in the Theaetetus and the Meno is his work "Is Justified True Belief Knowledge (1963)" where he develops the Gettier problem, an example of the type of scenario which challenges the notion that a justified true belief is the same thing as knowledge.
